XmlSerializer Constructors

Definition

Namespace:

System.Xml.Serialization

Assemblies:

netstandard.dll, System.Xml.XmlSerializer.dll

Initializes a new instance of the XmlSerializer class.

Overloads

XmlSerializer()	Initializes a new instance of the XmlSerializer class.
XmlSerializer(Type)	Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize XML documents into objects of the specified type.
XmlSerializer(XmlTypeMapping)	Initializes an instance of the XmlSerializer class using an object that maps one type to another.
XmlSerializer(Type, String)	Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize XML documents into objects of the specified type. Specifies the default namespace for all the XML elements.
XmlSerializer(Type, Type[])	Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize XML documents into object of a specified type. If a property or field returns an array, the extraTypes parameter specifies objects that can be inserted into the array.
XmlSerializer(Type, XmlAttributeOverrides)	Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize XML documents into objects of the specified type. Each object to be serialized can itself contain instances of classes, which this overload can override with other classes.
XmlSerializer(Type, XmlRootAttribute)	Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize an XML document into object of the specified type. It also specifies the class to use as the XML root element.
XmlSerializer(Type, XmlAttributeOverrides, Type[], XmlRootAttribute, String)	Initializes a new instance of the XmlSerializer class that can serialize objects of type Object into XML document instances, and deserialize XML document instances into objects of type Object. Each object to be serialized can itself contain instances of classes, which this overload overrides with other classes. This overload also specifies the default namespace for all the XML elements and the class to use as the XML root element.
XmlSerializer(Type, XmlAttributeOverrides, Type[], XmlRootAttribute, String, String)	Initializes a new instance of the XmlSerializer class that can serialize objects of type Object into XML document instances, and deserialize XML document instances into objects of type Object. Each object to be serialized can itself contain instances of classes, which this overload overrides with other classes. This overload also specifies the default namespace for all the XML elements and the class to use as the XML root element.

XmlSerializer()

Source:

XmlSerializer.cs

Initializes a new instance of the XmlSerializer class.

C#

protected XmlSerializer();

XmlSerializer(Type)

Source:

XmlSerializer.cs

Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize XML documents into objects of the specified type.

C#

public XmlSerializer(Type type);

Parameters

type

Type

The type of the object that this XmlSerializer can serialize.

Examples

The following example constructs an XmlSerializer that serializes an object named Widget. The example sets various properties of the object before calling the Serialize method.

C#

private void SerializeObject(string filename)
{
   XmlSerializer serializer =
   new XmlSerializer(typeof(OrderedItem));

   // Create an instance of the class to be serialized.
   OrderedItem i = new OrderedItem();

   // Set the public property values.
   i.ItemName = "Widget";
   i.Description = "Regular Widget";
   i.Quantity = 10;
   i.UnitPrice = (decimal) 2.30;

   // Writing the document requires a TextWriter.
   TextWriter writer = new StreamWriter(filename);

   // Serialize the object, and close the TextWriter.
   serializer.Serialize(writer, i);
   writer.Close();
}

// This is the class that will be serialized.
public class OrderedItem
{
   public string ItemName;
   public string Description;
   public decimal UnitPrice;
   public int Quantity;
}

Remarks

Commonly, an application defines several classes that the XmlSerializer converts into a single XML-instance document. However, the XmlSerializer must know only one type--the type of the class that represents the XML root element. The XmlSerializer automatically serializes all subordinate class instances. Similarly, only the type of the XML root element is required for deserialization.

See also

• Serialize(TextWriter, Object)
• Deserialize(Stream)
• XmlAttributes
• Introducing XML Serialization
• How to: Specify an Alternate Element Name for an XML Stream
• Controlling XML Serialization Using Attributes
• Examples of XML Serialization
• XML Schema Definition Tool (Xsd.exe)

XmlSerializer(XmlTypeMapping)

Source:

XmlSerializer.cs

Initializes an instance of the XmlSerializer class using an object that maps one type to another.

C#

public XmlSerializer(System.Xml.Serialization.XmlTypeMapping xmlTypeMapping);

Parameters

xmlTypeMapping

XmlTypeMapping

An XmlTypeMapping that maps one type to another.

Examples

The following example serializes a class named Group. The serialization of the GroupName, IgnoreThis fields, and the members of the GroupType enumeration are overridden. In the CreateOverrideSerializer method, a SoapAttributeOverrides object is created, and for each overridden member or enumeration, a SoapAttributes object is created with the appropriate property set and added to the SoapAttributeOverrides object. An XmlMapping object is created using the SoapAttributeOverrides object, and that XmlMapping object is used to create the XmlSerializer that overrides the default serialization.

C#

using System;
using System.IO;
using System.Text;
using System.Xml;
using System.Xml.Serialization;
using System.Xml.Schema;

public class Group
{
   [SoapAttribute (Namespace = "http://www.cpandl.com")]
   public string GroupName;

   [SoapAttribute(DataType = "base64Binary")]
   public Byte [] GroupNumber;

   [SoapAttribute(DataType = "date", AttributeName = "CreationDate")]
   public DateTime Today;
   [SoapElement(DataType = "nonNegativeInteger", ElementName = "PosInt")]
   public string PostitiveInt;
   // This is ignored when serialized unless it's overridden.
   [SoapIgnore]
   public bool IgnoreThis;

   public GroupType Grouptype;

   public Vehicle MyVehicle;

   // The SoapInclude allows the method to return a Car.
   [SoapInclude(typeof(Car))]
   public Vehicle myCar(string licNumber)
   {
      Vehicle v;
      if(licNumber == "")
         {
            v = new Car();
        v.licenseNumber = "!!!!!!";
     }
      else
     {
       v = new Car();
       v.licenseNumber = licNumber;
     }
      return v;
   }
}

// SoapInclude allows Vehicle to accept Car type.
[SoapInclude(typeof(Car))]
public abstract class Vehicle
{
   public string licenseNumber;
   public DateTime makeDate;
}

public class Car: Vehicle
{
}

public enum GroupType
{
   // These enums can be overridden.
   [SoapEnum("Small")]
   A,
   [SoapEnum("Large")]
   B
}

public class Run
{
   public static void Main()
   {
      Run test = new Run();
      test.SerializeOriginal("SoapOriginal.xml");
      test.SerializeOverride("SoapOverrides.xml");
      test.DeserializeOriginal("SoapOriginal.xml");
      test.DeserializeOverride("SoapOverrides.xml");
   }
   public void SerializeOriginal(string filename)
   {
      // Create an instance of the XmlSerializer class.
      XmlTypeMapping myMapping =
      (new SoapReflectionImporter().ImportTypeMapping(
      typeof(Group)));
      XmlSerializer mySerializer =
      new XmlSerializer(myMapping);
      Group myGroup=MakeGroup();
      // Writing the file requires a TextWriter.
      XmlTextWriter writer =
      new XmlTextWriter(filename, Encoding.UTF8);
      writer.Formatting = Formatting.Indented;
      writer.WriteStartElement("wrapper");
      // Serialize the class, and close the TextWriter.
      mySerializer.Serialize(writer, myGroup);
      writer.WriteEndElement();
      writer.Close();
   }

   public void SerializeOverride(string filename)
   {
      // Create an instance of the XmlSerializer class
      // that overrides the serialization.
      XmlSerializer overRideSerializer = CreateOverrideSerializer();
      Group myGroup=MakeGroup();
      // Writing the file requires a TextWriter.
      XmlTextWriter writer =
      new XmlTextWriter(filename, Encoding.UTF8);
      writer.Formatting = Formatting.Indented;
      writer.WriteStartElement("wrapper");
      // Serialize the class, and close the TextWriter.
      overRideSerializer.Serialize(writer, myGroup);
      writer.WriteEndElement();
      writer.Close();
   }

   private Group MakeGroup(){
      // Create an instance of the class that will be serialized.
      Group myGroup = new Group();

      // Set the object properties.
      myGroup.GroupName = ".NET";

      Byte [] hexByte = new Byte[2]{Convert.ToByte(100),
      Convert.ToByte(50)};
      myGroup.GroupNumber = hexByte;

      DateTime myDate = new DateTime(2002,5,2);
      myGroup.Today = myDate;
      myGroup.PostitiveInt= "10000";
      myGroup.IgnoreThis=true;
      myGroup.Grouptype= GroupType.B;
      Car thisCar =(Car)  myGroup.myCar("1234566");
      myGroup.MyVehicle=thisCar;
      return myGroup;
   }   	

   public void DeserializeOriginal(string filename)
   {
      // Create an instance of the XmlSerializer class.
      XmlTypeMapping myMapping =
      (new SoapReflectionImporter().ImportTypeMapping(
      typeof(Group)));
      XmlSerializer mySerializer =
      new XmlSerializer(myMapping);

      // Reading the file requires an  XmlTextReader.
      XmlTextReader reader=
      new XmlTextReader(filename);
      reader.ReadStartElement("wrapper");

      // Deserialize and cast the object.
      Group myGroup;
      myGroup = (Group) mySerializer.Deserialize(reader);
      reader.ReadEndElement();
      reader.Close();
   }

   public void DeserializeOverride(string filename)
   {
      // Create an instance of the XmlSerializer class.
      XmlSerializer overRideSerializer = CreateOverrideSerializer();

      // Reading the file requires an  XmlTextReader.
      XmlTextReader reader=
      new XmlTextReader(filename);
      reader.ReadStartElement("wrapper");

      // Deserialize and cast the object.
      Group myGroup;
      myGroup = (Group) overRideSerializer.Deserialize(reader);
      reader.ReadEndElement();
      reader.Close();
      ReadGroup(myGroup);
   }

   private void ReadGroup(Group myGroup){
      Console.WriteLine(myGroup.GroupName);
      Console.WriteLine(myGroup.GroupNumber[0]);
      Console.WriteLine(myGroup.GroupNumber[1]);
      Console.WriteLine(myGroup.Today);
      Console.WriteLine(myGroup.PostitiveInt);
      Console.WriteLine(myGroup.IgnoreThis);
      Console.WriteLine();
   }
   private XmlSerializer CreateOverrideSerializer()
   {
      SoapAttributeOverrides mySoapAttributeOverrides =
      new SoapAttributeOverrides();
      SoapAttributes soapAtts = new SoapAttributes();

      SoapElementAttribute mySoapElement = new SoapElementAttribute();
      mySoapElement.ElementName = "xxxx";
      soapAtts.SoapElement = mySoapElement;
      mySoapAttributeOverrides.Add(typeof(Group), "PostitiveInt",
      soapAtts);

      // Override the IgnoreThis property.
      SoapIgnoreAttribute myIgnore = new SoapIgnoreAttribute();
      soapAtts = new SoapAttributes();
      soapAtts.SoapIgnore = false;
      mySoapAttributeOverrides.Add(typeof(Group), "IgnoreThis",
      soapAtts);

      // Override the GroupType enumeration.	
      soapAtts = new SoapAttributes();
      SoapEnumAttribute xSoapEnum = new SoapEnumAttribute();
      xSoapEnum.Name = "Over1000";
      soapAtts.SoapEnum = xSoapEnum;

      // Add the SoapAttributes to the
      // mySoapAttributeOverridesrides object.
      mySoapAttributeOverrides.Add(typeof(GroupType), "A",
      soapAtts);

      // Create second enumeration and add it.
      soapAtts = new SoapAttributes();
      xSoapEnum = new SoapEnumAttribute();
      xSoapEnum.Name = "ZeroTo1000";
      soapAtts.SoapEnum = xSoapEnum;
      mySoapAttributeOverrides.Add(typeof(GroupType), "B",
      soapAtts);

      // Override the Group type.
      soapAtts = new SoapAttributes();
      SoapTypeAttribute soapType = new SoapTypeAttribute();
      soapType.TypeName = "Team";
      soapAtts.SoapType = soapType;
      mySoapAttributeOverrides.Add(typeof(Group),soapAtts);

      // Create an XmlTypeMapping that is used to create an instance
      // of the XmlSerializer. Then return the XmlSerializer object.
      XmlTypeMapping myMapping = (new SoapReflectionImporter(
      mySoapAttributeOverrides)).ImportTypeMapping(typeof(Group));
    
      XmlSerializer ser = new XmlSerializer(myMapping);
      return ser;
   }
}

Remarks

This constructor is used to create an XmlSerializer when you serialize an object into a SOAP message. To control the SOAP messages generated, use the special attributes (beginning with the word "Soap") found in the System.Xml.Serialization namespace.

See also

• XmlAttributes
• Introducing XML Serialization
• How to: Specify an Alternate Element Name for an XML Stream
• Controlling XML Serialization Using Attributes
• Examples of XML Serialization
• XML Schema Definition Tool (Xsd.exe)

XmlSerializer(Type, String)

Source:

XmlSerializer.cs

Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize XML documents into objects of the specified type. Specifies the default namespace for all the XML elements.

C#

public XmlSerializer(Type type, string? defaultNamespace);

Parameters

type

Type

The type of the object that this XmlSerializer can serialize.

defaultNamespace

String

The default namespace to use for all the XML elements.

Examples

The following example constructs an XmlSerializer that serializes an object named Widget. The example sets various properties of the object before calling the Serialize method.

C#

private void SerializeObject(string filename) {
    XmlSerializer serializer = new XmlSerializer
        (typeof(OrderedItem), "http://www.cpandl.com");

    // Create an instance of the class to be serialized.
    OrderedItem i = new OrderedItem();

    // Insert code to set property values.

    // Writing the document requires a TextWriter.
    TextWriter writer = new StreamWriter(filename);
    // Serialize the object, and close the TextWriter
    serializer.Serialize(writer, i);
    writer.Close();
}

private void DeserializeObject(string filename) {
    XmlSerializer serializer = new XmlSerializer
        (typeof(OrderedItem), "http://www.cpandl.com");
    // A FileStream is needed to read the XML document.
    FileStream fs = new FileStream(filename, FileMode.Open);

    // Declare an object variable of the type to be deserialized.
    OrderedItem i;

    // Deserialize the object.
    i = (OrderedItem) serializer.Deserialize(fs);

    // Insert code to use the properties and methods of the object.
}

See also

• XmlAttributes
• Introducing XML Serialization
• How to: Specify an Alternate Element Name for an XML Stream
• Controlling XML Serialization Using Attributes
• Examples of XML Serialization
• XML Schema Definition Tool (Xsd.exe)

XmlSerializer(Type, Type[])

Source:

XmlSerializer.cs

Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize XML documents into object of a specified type. If a property or field returns an array, the extraTypes parameter specifies objects that can be inserted into the array.

C#

public XmlSerializer(Type type, Type[]? extraTypes);

Parameters

type

Type

The type of the object that this XmlSerializer can serialize.

extraTypes

Type[]

A Type array of additional object types to serialize.

Examples

The following example serializes an instance of a class that contains a public field that returns an array of objects. The extraTypes parameter of the XmlSerializer constructor specifies the types of the objects that can be serialized in the array.

C#

using System;
using System.IO;
using System.Xml;
using System.Xml.Serialization;

// This defines the object that will be serialized.
public class Teacher
{
   public string Name;
   public Teacher(){}
   /* Note that the Info field returns an array of objects.
      Any object can be added to the array by adding the
      object type to the array passed to the extraTypes argument. */
   [XmlArray (ElementName = "ExtraInfo", IsNullable = true)]
   public object[] Info;
   public Phone PhoneInfo;
}

// This defines one of the extra types to be included.
public class Address
{
   public string City;

   public Address(){}
   public Address(string city)
   {
      City = city;
   }
}

// Another extra type to include.
public class Phone
{
   public string PhoneNumber;
   public Phone(){}
   public Phone(string phoneNumber)
   {
      PhoneNumber = phoneNumber;
   }
}

// Another type, derived from Phone
public class InternationalPhone:Phone
{
   public string CountryCode;

   public InternationalPhone(){}

   public InternationalPhone(string countryCode)
   {
      CountryCode = countryCode;
   }
}

public class Run
{
   public static void Main()
   {
      Run test = new Run();
      test.SerializeObject("Teacher.xml");
      test.DeserializeObject("Teacher.xml");
   }

   private void SerializeObject(string filename)
   {
      // Writing the file requires a TextWriter.
      TextWriter myStreamWriter = new StreamWriter(filename);

      // Create a Type array.
      Type [] extraTypes= new Type[3];
      extraTypes[0] = typeof(Address);
      extraTypes[1] = typeof(Phone);
      extraTypes[2] = typeof(InternationalPhone);

      // Create the XmlSerializer instance.
      XmlSerializer mySerializer = new XmlSerializer
      (typeof(Teacher),extraTypes);

      Teacher teacher = new Teacher();
      teacher.Name = "Mike";
      // Add extra types to the Teacher object
      object [] info = new object[2];
      info[0] = new Address("Springville");
      info[1] = new Phone("555-0100");

      teacher.Info = info;

      teacher.PhoneInfo = new InternationalPhone("000");

      mySerializer.Serialize(myStreamWriter,teacher);
      myStreamWriter.Close();
   }

   private void DeserializeObject(string filename)
   {
      // Create a Type array.
      Type [] extraTypes= new Type[3];
      extraTypes[0] = typeof(Address);
      extraTypes[1] = typeof(Phone);
      extraTypes[2] = typeof(InternationalPhone);

      // Create the XmlSerializer instance.
      XmlSerializer mySerializer = new XmlSerializer
      (typeof(Teacher),extraTypes);

      // Reading a file requires a FileStream.
      FileStream fs = new FileStream(filename, FileMode.Open);
      Teacher teacher = (Teacher) mySerializer.Deserialize(fs);

      // Read the extra information.
      Address a = (Address)teacher.Info[0];
      Phone p = (Phone) teacher.Info[1];
      InternationalPhone Ip =
      (InternationalPhone) teacher.PhoneInfo;

      Console.WriteLine(teacher.Name);
      Console.WriteLine(a.City);
      Console.WriteLine(p.PhoneNumber);
      Console.WriteLine(Ip.CountryCode);
   }
}

Remarks

By default, if a public property or field returns an object, or array of objects, the object types are automatically serialized. However, if a class contains a field or property that returns an array of type Object, any object can be inserted into that array. In that case, the XmlSerializer must be instructed to expect all the possible object types that are inserted into the Object array. To do this, use the extraTypes parameter to specify the extra object types to serialize or deserialize.

You can also use the extraTypes parameter to specify types derived from a base class. For example, suppose a base class named Phone exists, and a class named InternationalPhone derives from it. Use the extraTypes parameter to specify the derived type as well.

See also

• XmlAttributes
• Introducing XML Serialization
• How to: Specify an Alternate Element Name for an XML Stream
• Controlling XML Serialization Using Attributes
• Examples of XML Serialization
• XML Schema Definition Tool (Xsd.exe)

XmlSerializer(Type, XmlAttributeOverrides)

Source:

XmlSerializer.cs

Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize XML documents into objects of the specified type. Each object to be serialized can itself contain instances of classes, which this overload can override with other classes.

C#

public XmlSerializer(Type type, System.Xml.Serialization.XmlAttributeOverrides? overrides);

Parameters

type

Type

The type of the object to serialize.

overrides

XmlAttributeOverrides

An XmlAttributeOverrides.

Examples

The following example serializes an instance of a class that is defined in a DLL and to do so, overrides the public members found in the DLL.

C#

// Beginning of HighSchool.dll
namespace HighSchool
{
   public class Student
   {
      public string Name;
      public int ID;
   }

   public class MyClass
   {
      public Student[] Students;
   }
}

namespace College
   {
   using System;
   using System.IO;
   using System.Xml;
   using System.Xml.Serialization;
   using HighSchool;

    public class Graduate:HighSchool.Student
    {
       public Graduate(){}
       // Add a new field named University.
       public string University;
    }

   public class Run
   {
      public static void Main()
      {
         Run test = new Run();
         test.WriteOverriddenAttributes("College.xml");
         test.ReadOverriddenAttributes("College.xml");
      }

      private void WriteOverriddenAttributes(string filename)
      {
         // Writing the file requires a TextWriter.
         TextWriter myStreamWriter = new StreamWriter(filename);
         // Create an XMLAttributeOverrides class.
         XmlAttributeOverrides attrOverrides =
         new XmlAttributeOverrides();
         // Create the XmlAttributes class.
         XmlAttributes attrs = new XmlAttributes();

         /* Override the Student class. "Alumni" is the name
         of the overriding element in the XML output. */
         XmlElementAttribute attr =
         new XmlElementAttribute("Alumni", typeof(Graduate));

         /* Add the XmlElementAttribute to the collection of
         elements in the XmlAttributes object. */
         attrs.XmlElements.Add(attr);

         /* Add the XmlAttributes to the XmlAttributeOverrides.
         "Students" is the name being overridden. */
         attrOverrides.Add(typeof(HighSchool.MyClass),
         "Students", attrs);

         // Create the XmlSerializer.
         XmlSerializer mySerializer = new XmlSerializer
         (typeof(HighSchool.MyClass), attrOverrides);

         MyClass myClass = new MyClass();

         Graduate g1 = new Graduate();
         g1.Name = "Jackie";
         g1.ID = 1;
         g1.University = "Alma Mater";

         Graduate g2 = new Graduate();
         g2.Name = "Megan";
         g2.ID = 2;
         g2.University = "CM";

         Student[] myArray = {g1,g2};
         myClass.Students = myArray;

         mySerializer.Serialize(myStreamWriter, myClass);
         myStreamWriter.Close();
      }

      private void ReadOverriddenAttributes(string filename)
      {
         /* The majority of the code here is the same as that in the
         WriteOverriddenAttributes method. Because the XML being read
         doesn't conform to the schema defined by the DLL, the
         XMLAttributesOverrides must be used to create an
         XmlSerializer instance to read the XML document.*/

         XmlAttributeOverrides attrOverrides = new
         XmlAttributeOverrides();
         XmlAttributes attrs = new XmlAttributes();
         XmlElementAttribute attr =
         new XmlElementAttribute("Alumni", typeof(Graduate));
         attrs.XmlElements.Add(attr);
         attrOverrides.Add(typeof(HighSchool.MyClass),
         "Students", attrs);

         XmlSerializer readSerializer = new XmlSerializer
         (typeof(HighSchool.MyClass), attrOverrides);

         // To read the file, a FileStream object is required.
         FileStream fs = new FileStream(filename, FileMode.Open);

         MyClass myClass;

         myClass = (MyClass) readSerializer.Deserialize(fs);

         /* Here is the difference between reading and writing an
         XML document: You must declare an object of the derived
         type (Graduate) and cast the Student instance to it.*/
         Graduate g;

         foreach(Graduate grad in myClass.Students)
         {
            g = (Graduate) grad;
            Console.Write(g.Name + "\t");
            Console.Write(g.ID + "\t");
            Console.Write(g.University + "\n");
         }
      }
   }
}

Remarks

The overrides parameter can be used to control how fields and properties are encoded in XML. These settings override any attributes that already exist on the objects. This can be useful when the source code cannot be modified or multiple encodings are required for the same classes.

See also

• XmlAttributeOverrides
• XmlAttributes
• Introducing XML Serialization
• How to: Specify an Alternate Element Name for an XML Stream
• Controlling XML Serialization Using Attributes
• Examples of XML Serialization
• XML Schema Definition Tool (Xsd.exe)

XmlSerializer(Type, XmlRootAttribute)

Source:

XmlSerializer.cs

Initializes a new instance of the XmlSerializer class that can serialize objects of the specified type into XML documents, and deserialize an XML document into object of the specified type. It also specifies the class to use as the XML root element.

C#

public XmlSerializer(Type type, System.Xml.Serialization.XmlRootAttribute? root);

Parameters

type

Type

The type of the object that this XmlSerializer can serialize.

root

XmlRootAttribute

An XmlRootAttribute that represents the XML root element.

Examples

The following example constructs an XmlSerializer that uses an XmlRootAttribute that contains various properties of the XML root element, such as its namespace and element name.

C#

private void SerializeObject(string filename) {
    // Create an XmlRootAttribute, and set its properties.
    XmlRootAttribute xRoot = new XmlRootAttribute();
    xRoot.ElementName = "CustomRoot";
    xRoot.Namespace = "http://www.cpandl.com";
    xRoot.IsNullable = true;

    // Construct the XmlSerializer with the XmlRootAttribute.
    XmlSerializer serializer = new XmlSerializer
        (typeof(OrderedItem),xRoot);

    // Create an instance of the object to serialize.
    OrderedItem i = new OrderedItem();
    // Insert code to set properties of the ordered item.

    // Writing the document requires a TextWriter.
    TextWriter writer = new StreamWriter(filename);

    serializer.Serialize(writer, i);
    writer.Close();
}

private void DeserializeObject(string filename) {
    // Create an XmlRootAttribute, and set its properties.
    XmlRootAttribute xRoot = new XmlRootAttribute();
    xRoot.ElementName = "CustomRoot";
    xRoot.Namespace = "http://www.cpandl.com";
    xRoot.IsNullable = true;

    XmlSerializer serializer = new XmlSerializer
        (typeof(OrderedItem),xRoot);

    // A FileStream is needed to read the XML document.
    FileStream fs = new FileStream(filename, FileMode.Open);
    // Deserialize the object.
    OrderedItem i = (OrderedItem) serializer.Deserialize(fs);
    // Insert code to use the object's properties and methods.
}

Remarks

The root element of an XML document encloses all the other elements. By default, the object specified by the type parameter is serialized as the root element. Properties, such as the XML element name of the root element, are taken from the type object. However, the root parameter allows you to replace the default object's information by specifying an XmlRootAttribute; the object allows you to set a different namespace, element name, and so on.

See also

• XmlAttributes
• Introducing XML Serialization
• How to: Specify an Alternate Element Name for an XML Stream
• Controlling XML Serialization Using Attributes
• Examples of XML Serialization
• XML Schema Definition Tool (Xsd.exe)

XmlSerializer(Type, XmlAttributeOverrides, Type[], XmlRootAttribute, String)

Source:

XmlSerializer.cs

Initializes a new instance of the XmlSerializer class that can serialize objects of type Object into XML document instances, and deserialize XML document instances into objects of type Object. Each object to be serialized can itself contain instances of classes, which this overload overrides with other classes. This overload also specifies the default namespace for all the XML elements and the class to use as the XML root element.

C#

public XmlSerializer(Type type, System.Xml.Serialization.XmlAttributeOverrides? overrides, Type[]? extraTypes, System.Xml.Serialization.XmlRootAttribute? root, string? defaultNamespace);

Parameters

type

Type

The type of the object that this XmlSerializer can serialize.

overrides

XmlAttributeOverrides

An XmlAttributeOverrides that extends or overrides the behavior of the class specified in the type parameter.

extraTypes

Type[]

A Type array of additional object types to serialize.

root

XmlRootAttribute

An XmlRootAttribute that defines the XML root element properties.

defaultNamespace

String

The default namespace of all XML elements in the XML document.

Examples

The following example serializes an instance of a class that is defined in a DLL and to do so, overrides the public members found in the class. The example also specifies an array of extra types, the default namespace for all XML elements, and the class to use that provides the XML root element information. The example assumes that the code at the beginning has been compiled into a DLL named HighSchool.

C#

// Beginning of the HighSchool.dll

namespace HighSchool
{
   public class Student
   {
      public string Name;
      public int ID;
   }

   public class MyClass
   {
      public Student[] Students;
   }
}

namespace College
   {
   using System;
   using System.IO;
   using System.Xml;
   using System.Xml.Serialization;
   using HighSchool;

    public class Graduate:HighSchool.Student
    {
       public Graduate(){}
       // Add a new field named University.
       public string University;
       // Use extra types to use this field.
       public object[]Info;
    }

    public class Address
    {
       public string City;
    }

    public class Phone
    {
       public string Number;
    }

   public class Run
   {
      public static void Main()
      {
         Run test = new Run();
         test.WriteOverriddenAttributes("College.xml");
         test.ReadOverriddenAttributes("College.xml");
      }

      private void WriteOverriddenAttributes(string filename)
      {
         // Writing the file requires a TextWriter.
         TextWriter myStreamWriter = new StreamWriter(filename);
         // Create an XMLAttributeOverrides class.
         XmlAttributeOverrides attrOverrides =
         new XmlAttributeOverrides();
         // Create the XmlAttributes class.
         XmlAttributes attrs = new XmlAttributes();
         /* Override the Student class. "Alumni" is the name
         of the overriding element in the XML output. */

         XmlElementAttribute attr =
         new XmlElementAttribute("Alumni", typeof(Graduate));
         /* Add the XmlElementAttribute to the collection of
         elements in the XmlAttributes object. */
         attrs.XmlElements.Add(attr);
         /* Add the XmlAttributes to the XmlAttributeOverrides.
         "Students" is the name being overridden. */
         attrOverrides.Add(typeof(HighSchool.MyClass),
         "Students", attrs);

         // Create array of extra types.
         Type [] extraTypes = new Type[2];
         extraTypes[0]=typeof(Address);
         extraTypes[1]=typeof(Phone);

         // Create an XmlRootAttribute.
         XmlRootAttribute root = new XmlRootAttribute("Graduates");

         /* Create the XmlSerializer with the
         XmlAttributeOverrides object. */
         XmlSerializer mySerializer = new XmlSerializer
         (typeof(HighSchool.MyClass), attrOverrides, extraTypes,
         root, "http://www.microsoft.com");

         MyClass myClass= new MyClass();

         Graduate g1 = new Graduate();
         g1.Name = "Jacki";
         g1.ID = 1;
         g1.University = "Alma";

         Graduate g2 = new Graduate();
         g2.Name = "Megan";
         g2.ID = 2;
         g2.University = "CM";

         Student[] myArray = {g1,g2};

         myClass.Students = myArray;

         // Create extra information.
         Address a1 = new Address();
         a1.City = "Ionia";
         Address a2 = new Address();
         a2.City = "Stamford";
         Phone p1 = new Phone();
         p1.Number = "555-0101";
         Phone p2 = new Phone();
         p2.Number = "555-0100";

         Object[]o1 = new Object[2]{a1, p1};
         Object[]o2 = new Object[2]{a2,p2};

         g1.Info = o1;
         g2.Info = o2;
         mySerializer.Serialize(myStreamWriter,myClass);
         myStreamWriter.Close();
      }

      private void ReadOverriddenAttributes(string filename)
      {
         /* The majority of the code here is the same as that in the
         WriteOverriddenAttributes method. Because the XML being read
         doesn't conform to the schema defined by the DLL, the
         XMLAttributesOverrides must be used to create an
         XmlSerializer instance to read the XML document.*/

         XmlAttributeOverrides attrOverrides = new
         XmlAttributeOverrides();
         XmlAttributes attrs = new XmlAttributes();
         XmlElementAttribute attr =
         new XmlElementAttribute("Alumni", typeof(Graduate));
         attrs.XmlElements.Add(attr);
         attrOverrides.Add(typeof(HighSchool.MyClass),
         "Students", attrs);

         Type [] extraTypes = new Type[2];
         extraTypes[0] = typeof(Address);
         extraTypes[1] = typeof(Phone);

         XmlRootAttribute root = new XmlRootAttribute("Graduates");

         XmlSerializer readSerializer = new XmlSerializer
         (typeof(HighSchool.MyClass), attrOverrides, extraTypes,
         root, "http://www.microsoft.com");

         // A FileStream object is required to read the file.
         FileStream fs = new FileStream(filename, FileMode.Open);

         MyClass myClass;
         myClass = (MyClass) readSerializer.Deserialize(fs);

         /* Here is the difference between reading and writing an
         XML document: You must declare an object of the derived
         type (Graduate) and cast the Student instance to it.*/
         Graduate g;
         Address a;
         Phone p;
         foreach(Graduate grad in myClass.Students)
         {
            g = (Graduate) grad;
            Console.Write(g.Name + "\t");
            Console.Write(g.ID + "\t");
            Console.Write(g.University + "\n");
            a = (Address) g.Info[0];
            Console.WriteLine(a.City);
            p = (Phone) g.Info[1];
            Console.WriteLine(p.Number);
         }
      }
   }
}

Remarks

The overrides parameter allows for the creation of an XmlSerializer that serializes a class that extends or overrides the behavior of a base class. For example, given a DLL, it is possible to create a class that inherits or extends a class contained in the DLL. To serialize such a class, you must use an instance of the XmlAttributeOverrides class when constructing the XmlSerializer. For more details, see XmlAttributeOverrides.

By default, if a public property or field returns an object, or array of objects, the object types are automatically serialized. However, if a class contains a field or property that returns an array of type Object, any object can be inserted into that array. In that case, the XmlSerializer must be instructed to expect all the possible object types that are inserted into the Object array. To do this, use the extraTypes parameter to specify the extra object types to serialize or deserialize.

The root element of an XML document encloses all the other elements. By default, the object specified by the type parameter is serialized as the root element. Properties, such as the XML element name of the root element are taken from the type object. However, the root parameter allows you to replace the default object's information by specifying an XmlRootAttribute; the object allows you to set a different namespace, element name, and so on.

Use the defaultName parameter to specify the default namespace of all XML elements generated by the XmlSerializer.

See also

• XmlAttributeOverrides
• XmlRootAttribute
• XmlAttributes
• Introducing XML Serialization
• How to: Specify an Alternate Element Name for an XML Stream
• Controlling XML Serialization Using Attributes
• Examples of XML Serialization
• XML Schema Definition Tool (Xsd.exe)

XmlSerializer(Type, XmlAttributeOverrides, Type[], XmlRootAttribute, String, String)

Source:

XmlSerializer.cs

Initializes a new instance of the XmlSerializer class that can serialize objects of type Object into XML document instances, and deserialize XML document instances into objects of type Object. Each object to be serialized can itself contain instances of classes, which this overload overrides with other classes. This overload also specifies the default namespace for all the XML elements and the class to use as the XML root element.

C#

public XmlSerializer(Type type, System.Xml.Serialization.XmlAttributeOverrides? overrides, Type[]? extraTypes, System.Xml.Serialization.XmlRootAttribute? root, string? defaultNamespace, string? location);

Parameters

type

Type

The type of the object that this XmlSerializer can serialize.

overrides

XmlAttributeOverrides

An XmlAttributeOverrides that extends or overrides the behavior of the class specified in the type parameter.

extraTypes

Type[]

A Type array of additional object types to serialize.

root

XmlRootAttribute

An XmlRootAttribute that defines the XML root element properties.

defaultNamespace

String

The default namespace of all XML elements in the XML document.

location

String

The location of the types.